<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>蓝旭第三次作业3</title>
</head>

<body>
    <script>
        var r = new Number(2);

        function area(r) {
            var s = Math.PI * r * r;
            console.log(s);
            return s;
        }
        s = area(r);
    </script>
</body>

</html>